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"Paul Dalen" <> wrote in message
news:aleSb.10161$Q_4.7172@okepread03...
> Is it possible to reverse an EF lens? I mean, to install it backwards (on
> purpose)?
>
>
Yes it is, but there are better ways to get macro results with said Canon
cameras. I guess given the correct adapter you could even mount it backwards
accidently.

It would probably be feasible for the average do-it-yourself guy to make
such an adapter from an EF extension ring cut in two pieces, and a filter
adapter ring glued to the piece that mounts on the body. I wonder if anyone
has made such an accessory?

Paul Dalen wrote:
>
> Is it possible to reverse an EF lens? I mean, to install it backwards (on
> purpose)?

Yes, you need a reversing adapter - one such (may be the only one, my UK
dealer's catalogue claims it's unique) is made by Novoflex and comprises
one adapter that fits on the front of the camera (to which the front of
the lens is screwed) and a second fitted to the back of the lens (which
is now at the ront) to provide the EF connections. The two parts are
cable linked.
In the UK it retails for around £190, so it's probably around $200-250.
Novoflex product page is at;http://www.novoflex.de/english/html/products.htm

Does reversing give more magnification than using extension tubes? I
suppose it depends on the lense combination. probably some formula to
determine the magnification factor. But, with extension tubes, you get
AF and aperture control. I have the Kenko ext tubes...and they get me as
close as I've wanted so far

rr

PhotoMan wrote:
> "Paul Dalen" <> wrote in message
> news:aleSb.10161$Q_4.7172@okepread03...
>
>>Is it possible to reverse an EF lens? I mean, to install it backwards (on
>>purpose)
>
>
> HP Photo in New York has the reversing adapters. Note: you will have no AF
> or aperture control.
> Joe Arnold
>
>

Yes. The 50/1.8 when reversed, covers about 35mm horizontally, or
approximately the same as when mounted on a 36mm extension ring. As an
additional benefit, the lens-to-subject distance is larger. And extension
rings can of course still be used for more magnification.
/N

"Randy Rhine" <> wrote in message
news:aKeSb.139392$sv6.755735@attbi_s52...
> Does reversing give more magnification than using extension tubes? I
> suppose it depends on the lense combination. probably some formula to
> determine the magnification factor. But, with extension tubes, you get
> AF and aperture control. I have the Kenko ext tubes...and they get me as
> close as I've wanted so far
>
> rr
>
>
>
> PhotoMan wrote:
> > "Paul Dalen" <> wrote in message
> > news:aleSb.10161$Q_4.7172@okepread03...
> >
> >>Is it possible to reverse an EF lens? I mean, to install it backwards
(on
> >>purpose)
> >
> >
> > HP Photo in New York has the reversing adapters. Note: you will have no
AF
> > or aperture control.
> > Joe Arnold
> >
> >
>

Randy Rhine <> wrote in
news:aKeSb.139392$sv6.755735@attbi_s52:
> Does reversing give more magnification than using extension tubes? I
> suppose it depends on the lense combination. probably some formula to
> determine the magnification factor. But, with extension tubes, you
> get AF and aperture control. I have the Kenko ext tubes...and they get
> me as close as I've wanted so far
>
> rr
>
>
>
> PhotoMan wrote:
>> "Paul Dalen" <> wrote in message
>> news:aleSb.10161$Q_4.7172@okepread03...
>>
>>>Is it possible to reverse an EF lens? I mean, to install it
>>>backwards (on purpose)
>>
>>
>> HP Photo in New York has the reversing adapters. Note: you will have
>> no AF or aperture control.
>> Joe Arnold
>>
>>
>

As I understand it, the reason some lenses are used reversed is because
they are designed so the focused plane (the film) at the back of the
lens is closer than objects at the front. After reversing, your subject
is then closer to the lens while the film is farther since you use a
bellows or tubes. However, results will vary depending on the
particular lens you use.
I have tried one that was able to focus reversed but had a lot of field
curvature so the edges looked bad. Another I tried was not able to
focus at all when reversed. The best results I've gotten were from a
regularly mounted 100mm macro lens. The 1:1 ratio I get from it is more
than enough for my uses, but tubes could be used to get closer if
needed.

the typical photographic lens is optimized for imaging far away objects onto a
near-by sensor (film). 'Optimised' refers to correcting abberations of light
tracing through the lens, mainly diminishing geometric and colour 'errors'.
This correction is sensitive to the distance of the object to the lens.

Obviously 'macro' shots don't fit the bill of this optimisation because in a
macro shot situation the object is positioned near to the lens and the distance
between sensor (film) and lens has to be quite large. When doing macro shots
the geometry of the imaging process is -so to speak- inversed with regard to
the design specifications of the lens. You might either buy a 'macro' lens or
place your lens inverted ('backwards') into the path of the light. The latter
was done routinely in earlier times when people used extension tubes for macro
shots.

When you are interested in these things I would urge you to buy some old
equipment, ideally a wooden camera of ancient times with a focusing screen, or
next to this ideal an old SLR with 'extension rings' for macro photography.
Equipment of this type can be bought very cheaply and it needn't be of high
quality for the purpose of gaining some first hand experience with optics. in
addition, a simple introductory text book on optics would be helpful, as well.

Unfortunately, the modern zoom lens design is incorporating some devilish
tricks that completly mask the very simple underlying physical priciples of
optics. You cant't get meaningful insights into optics from naive observation
anymore from this newfangled stuff.

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